Clinker production is very energy-intensive and responsible for releasing climate-relevant carbon dioxide (CO₂) into the atmosphere, and the exploitation of aggregate for concrete results in a reduction in natural resources. This contrasts with infrastructure development, surging urbanization, and the demand for construction materials with increasing requirements in terms of durability and strength. A possible answer to this is eco-efficient, high-performance concrete. This article illustrates basic material investigations to both, using eco-friendly cement and recycled aggregate from tunneling to produce structural concrete and inner shell concrete, showing high impermeability and durability. By replacing energy- and CO₂-intensive cement types by slag-pozzolanic cement (CEM V) and using recycled aggregate, a significant contribution to environmental sustainability can be provided while still meeting the material requirements to achieve a service lifetime for the tunnel structure of up to 200 years. Results of this research show that alternative cements (CEM V), as well as processed tunnel spoil, indicate good applicability in terms of their properties. Despite the substitution of conventional clinker and conventional aggregate, the concrete shows good workability and promising durability in conjunction with adequate concrete strengths.

Sodium bentonite (Na-bentonite) is used as a sealing component in geosynthetic clay liners (GCL). Na-bentonite is very sensitive to chlorides, and flocculation occurs when it is exposed to saline environments. The purpose of this work is to investigate the properties of Na-bentonite and bentonite–palygorskite filler material for GCL in saline solutions in the range between 0.5% and 10% (0.09 and 1.8 M) NaCl concentration. The investigation has been carried out to evaluate and study the chemical and geotechnical properties of Na-bentonite and bentonite–palygorskite mixture. The observations suggest that the resistance of Na-bentonite to chlorides is increased by adding 40% palygorskite. The bentonite–palygorskite mixture is characterised by high liquid and plastic limits, and also by high water adsorption and free swell in water, crude oil and petrol. Hydraulic conductivity was determined for water and for 10% NaCl (1.80 M) solution. The results show that Na-bentonite palygorskite mixture serves as an effective absorber of both water and saline solutions up to a concentration of 10% (1.80 M) of NaCl without increasing the hydraulic conductivity.

In addition to the known uses of natural clays, less publication attention has been paid to clays returned to the production process. Industrially recovered natural clays such as bricks, tiles, sanitary ceramics, ceramic roofing tiles, etc., are applicable in building materials based on concrete as an artificial recycled aggregate or as a pozzolanic type II addition. In this way, the building products with higher added value are obtained from the originally landfilled waste. This paper details the research process of introducing concrete with recycled brick waste (RBW) up to the application output. The emphasis is placed on using a RBW brash as a partial replacement for natural aggregates and evaluating an RBW powder as a type II addition for use in concrete. A set of the results for an RBW is reported by the following: (a) an artificial RBW fine aggregate meets the required standardized parameters for use in industrially made concrete, (b) a RBW powder is suitable for use in concrete as industrially made type II addition TERRAMENT showing the same pozzolanic reactivity as a well-known and broadly used pozzolan-fly ash, and (c) such an RBW as aggregate and as powder are, therefore, suitable for the production of industrially made TRITECH Eco-designed ready-mixed concrete.

The advancement of cement composites with different pozzolana types represents needful domain in civil engineering. Utility properties of such composites are closely approaching the level of standard quality. The raw materials – kaolin sand thermally transformed at 650°C/hour and clayey diatomite calcined at 900°C/hour were used in the experiment. Cement ternary composites containing 5 and 10wt.% of metakaolinite as well as 5 and 10wt.% of calcined clayey diatomite (in varied proportions) with water to solid ratio of 0.5 were manufactured for this study. The physical-mechanical and physical-chemical behaviour of relevant ternary systems after 28-days water curing are presented in this paper. Thermal analysis disclosed calciumsilicate hydrate (CSH) and calciumaluminate hydrate (CAH) formation, portlandite dehydroxylation and calcite decarbonation. Portlandite content reduction was found as a result of respective pozzolanic reaction unlike reference composite without pozzolana. This statement was confirmed by X-ray diffraction analysis. The favourable standard mechanical properties (compressive strength) in this study of composites were documented as well. Results exhibit the effective pozzolanic reaction susceptible the attainment of valuable utility properties of cement composites